District Cooling Through the Ages

While you may not think about it, the way we cool our homes has evolved massively over thousands of years.

From the millennia-old ‘barjeel’ wind towers that provided relief to our Middle Eastern forefathers, through to today’s energy-efficient district cooling, maintaining a comfortable temperature at home has led to countless hours of technological development and innovation, with origins dating back more than 3,000 years.

Climatic extremes have always driven society to seek ways in which to be more comfortable in indoor spaces. Evidence has been found in South Korea of ondol (underfloor) heating systems dating from around the 10th century BC Bronze Age era, while Greek and Roman methods of underfloor heating, better known as hypocausts, were widespread across Europe around 500 BC.

One of the first examples of district cooling, however, can possibly be attributed to the Romans, who used common aqueducts to pump cool water through pipes in their homes’ walls to lower temperatures in summer.

Cooling has always been linked to the way we construct our homes. The aforementioned technologies worked primarily because we lived in mostly single storey houses. And as the construction of our homes has evolved through history, so has the way we cool our homes. As we added more storeys to our houses, single unit air conditioners (commonly referred to as Window ACs) were used to cool indoor environments. However, these ACs were found to be noisy and inefficient (window ACs uses 2.2kW to produce one tonne of cooling). As a result, technological advancements gave way to central ACs and apartment-wide chiller systems and eventually, district cooling. And with each step, came incremental energy savings, making district cooling the most energy efficient of all the technologies. Think of the principle of the economies of large-scale where large production leads to lower cost of single units. When these systems covered wider areas, these new technologies resulted in lower energy usage per unit of cooling.

District cooling, as it is known today, is inspired by the predecessor technology, in that it is an energy-efficient way to provide cool air and chilled water to buildings across a defined area. Similar to the Roman aqueduct system, a district cooling plant produces and distributes cooling energy, sending chilled water through underground pipes to cool the indoor air of all connected buildings. Water is used by specialised units in each building to chill the air that passes through an air conditioning system, making summer days’ scorching temperatures far more bearable.

As a more efficient system that needs less than 1 kW to produce one tonne of cooling, district cooling saves up to 50% more energy than traditional window ACs, making it considerably more environmentally friendly. It also requires lower capital costs, lower operating costs, saves on space in buildings, and offers predictable, flexible costing as well as greater reliability than traditional units – which is no doubt why it’s become such a popular alternative.

With society’s continuous search for solutions that offer greater results while being less taxing on the environment, both in terms of fuel consumption and emissions, district cooling’s evolution is not yet complete. In fact, as demand for district cooling operations across the world grows to accommodate expanding communities and their chilled air and water needs, the technology powering the system is being constantly refined to make it even more efficient and more accessible.

When communities turn to district cooling over individual alternatives, they can collectively contribute to their society becoming more sustainable.

At Empower, we have made it our mission to supply sustainable solutions by delivering reliable, cost-effective and environmentally-friendly, world-class district cooling services. With a total cooling capacity of 1,045,000 refrigeration tonnes in 2014 for 62 connected buildings across the UAE, Empower’s district cooling solution saved 836 MW in power plant capacity last year, while serving 50,000 customers with chilled air.

Some might say that our goal of doubling our capacity over the next few years is ambitious. But with Dubai’s ambitious real estate plans, and government support for green technologies, our aims are not only achievable, but within close reach. As we work to provide thousands of customers with sustainable services, we like to think that the cooling technologies we use are an act of coming full circle with the resolutions of our ancestors.